A New Method of Terahertz Radar Calibration for Low SNR Signals

In this paper, we proposes a calibration method for terahertz SAR system, which can accurately calibrate the channel error by multi-impulse accumulation at low signal-to-noise ratio. Firstly, the range walk of point target is removed by range walk correction, and the region with less variation in the phase curve is used for multi-impulse accumulation; Secondly, the point target position is confirmed and the signal is converted to time domain, the phase information in the time domain signal is extracted, and the phase error function is obtained by linear fitting; finally, the phase error function is multiplied with the original time domain signal to complete the channel calibration. Compared with the original calibration method, the proposed method improves the adaptability and robustness for low SNR signals. It improves the phase compensation accuracy, and verifies the effectiveness of the method in the measured data of terahertz radar.